Opening the html file directly leads to a cross domain error on most browsers (I should remember to mention this in the README, but it's been a while since I've had time to think about this project.)
I assume you want to change the code and see the results locally. Two solutions: find a way to disable cross domain checks in you browser, or run a webserver in the downloaded folder (I use python in the command line and run 'python -m http.server').
You could also fork the code on github (link in credits) and use your own github.io to run it. This only works after pushing the changes online, so I prefer running it locally.
I will write better instructions when I have the time.